Vertically adjustable table for office appliances



March 20, 1951 w, GANNETT ETAL 2,545,515

VERTICALLY ADJUSTABLE "TABLE FOR OFFICE APPLIANCES Filed July 24, 1948 3 Sheets-Sheet 1 4 T TOP/YE) W. K. GANNETT ETAL VERTICALLY ADJUSTABLE TABLE FOR OFFICE APPLIANCES March 20, 1951 3 Sheegs-Sheet 2 Filed July 24, 1948 IN VEN TOR5 WP/GHT K. Cfl/V/VEZ'T Giii/m M457 Arm/Mb.

6 ,4 lilillllIH-IIHYF? H W I .i mm. W M 7 a AF I H numww v Patented Mar. 20, 1951 UNITED STATES PATENT OFFICE VERTIGALLY ADJUSTABLE TABLE FOR OFFICE APPLIANCES Wright K. Gannett and Gifiord M. Mast, Davenport, Iowa, assignors to Le Febure Corporation, Cedar Rapids, Iowa, a corporation of Iowa Application July 24, 1948, Serial No. 40,466

6 Claims; 1

This invention relates to elevating ofiice stands and has particular relation to an adjustable table structure suitable for supporting loose leaf ledgers, file boxes and like articles, at whatever height is most convenient for the user.

While numerou devices have been proposed for making table tops adjustable with relation to the floor, such devices have usually employed screw jacks, hydraulic jacks, or other similar mechanisms, and raising or lowering of the table required manipulation of these raising or lowering mechanisms. Others have been unreliable as well as relatively complicated and expensive to build.

A primary object of our invention is the provision of a dependable, elevating stand or adjustable table of simple construction and one having adequate capacity to handle any ordinary load likely to be placed upon it, but so arranged as to operate easily with but relatively little force applied directly to the table top.

It is imperative, in tables of the character considered, that the surface of the tabl to will always be level, regardless of its distance above the floor, and therefore another main object of our invention is to provide a table in which the top surface is maintained parallel to the plane of the floor, regardless of the height to which it is ad;- justed Still another object of our invention is to pro, vide simple means for compensating for variation in the weight of the load being carried on the table or supported thereby,

Other and further features and objects of the invention will be more apparent to those skilled in the art upon a consideration'of the accompanying drawings and following specification, wherein is disclosed a single exemplary embodiment of the invention, with the understanding, however, that such changes may be made therein as fall within the scope of the appended claims, without depart.- ing from the spirit of the invention.

In said-drawings;

Figure 1 is a View in perspective of an elevating table constructed according to a preferred ennbodiment fmy invention.

Figure 12'is a view in perspective of the table in collapsed or lowered position. The table is viewed from the end opposite that illustrated in Figure 1.

Figure 3 is a view, partly inside elevation and partly in longitudinal vertical section, of my eleva ns ab e, and

Figure 4 is a fragmentary View in end elevation of the device illustrating some of thedetails'of the "elevating-mechanism.

Referring now to these drawings, and in particular to Figures 1 and 2 thereof, in which a table top H is supported above a base member, indicated generally at 1-2, by means of a plurality of arms pivotally connected therebetween, the arms being so positioned as to form the sides of spaced parallelograms asv shown at 13. counterbalancing of the Weight of the table top H and any load placed upon it is accomplished by means of coiled tension springs I l operatively connected with the arms, as will be hereinafter more fully described, and by means of a tension adjustment indicated in general at it. The table top, when adjusted to suit the convenience of the user, is secured against further up-or-down movement by means of the locking mechanism H.

The base member I2 is of rectangular shape and preferably constructed of sheet metal in generally box-like form, as at B8, and supported at the corners by the casters t9;

A pair of plate-like base flanges 2! and 22 are secured, along, their lower edges, to the side walls of the base I2 adjacent one end thereof. These flanges may be of generally triangular shape and are apertured at vertically and horizontally spaced points to receive the pivot bolts 23 and 2d,

The table top H may also be of sheet metal construction having down-turned, flanged edges, as at 26, for rigidity. Additional reinforcing members 2l2"l, secured to the longitudinal edges of the top, extend thereabove te provide a partial rim. ,Depending from these longitudi' nal edges of the table to are a pair of top flanges 2'8 and 29 These members are preferably of similar shape to the base flanges 25 and 22, and in the same planes, and so positioned that the near edges 28a and 2m of each pair are sub-Stantially parallel.

The top flanges 28 and 2-9 are apertured in manner similar to the base flanges to ive pivot bolts 3: and-32 and at points such that the apertures and the bDltsOf' the companion flanges '31 being positioned between eachflan'ge andarm.

3 A tube-like spacer 38 is welded between the upper pivot arms 33 at their points of pivotal connection with the lower flanges, the ends of the spacer being plugged and tapped to receive the pivot bolts 2d.

The lower pivot arms 34 are extended at their lower ends to provide lever arms 39 between the ends of which a channel-shaped cross member 4| is attached by bolting or spot welding, as at 42.

The tension adjusting mechanism includes, in addition to the cross member M, an equalizer bar 43 of generally box-like form which is pivotally mounted between the lowermost ends of the lever arms 39 upon studs M which extend through openings in the end Walls 33a of the cross member.

Ear-like members 46 project outwardly from the movable wall ll, of this equalizer bar 43, adjacent each end thereof and are apertured, as at 38, to permit engagement with the hooked ends of the springs i i-i l. The opposite ends of the springs are engaged to anchor plates 49, which members are secured to the base at points sufficiently remote from the cross member 43 to create an initial tension in the springs. This initial tension should be such that, when the equalizer bar 43 is adjusted to the position illustrated at 431) by dotted lines, and at which position the effective lengths of the lever arms 39 are the shortest, the weight of the table top and attached movable mechanisms will be substantially coun terbalanced.

In order to move the equalizer bar 43 downwardly and thus increase the efiective length of the lever arms 39, We provide the threaded adjusting screw 5?. This screw is provided, near its upper end, with a collar 52 and an operating crank 53 spaced thereabove.

The crank is secured to the screw 55 by means of a pin 54, the shank of the screw being first passed through a transverse hole in a short swivel shaft 55. The ends of this swivel shaft are pivotally received in apertured angle plates 5'l5l and these members are riveted or welded to the underside of the cross member ll on opposite sides of the opening 58. This opening in the cross member provides for the passage therethrough of the shank of the adjusting screw and the hub of the crank 53.

A similar swivel shaft 59 is pivotally mounted between a pair of angle plates Bl and these angle plates are amxed to the inner surface of the movable wall ll of the equalizer bar generally as shown. The swivel shaft is, however, threaded to receive the adjusting screw, and stop or limit nuts 62 and 63 are threadedly received on the adjusting screw above and below the swivel shaft 59. These stop nuts are provided with set screws or lock nuts, not shown, to affix them in position.

It may now be understood that the angular relation of the equalizer bar 43 relative to the lever arms 39 may be altered by rotating the adjusting screw 5! to vary the effective lengths of the lever arms, this effective length being the distance between the centers of the pivot bolts 23 and the ear-like spring attachment members Q6 of the equalizer bar.

When the spring tensioning device is adjusted to its lowest possible position, as represented by solid lines, it provides lever arms of the greatest effective length. when so adjusted, the table will lift or carry its maximum load.

The relative positions of the table top, the pivot arms and the equalizer bar, when the top is in elevated position, are indicated by dashed lines in Figure 3.

Spring enclosures 6464, formed of sheet metal, extend upwardly from the base to enclose the springs on top and sides.

The locking mechanism 11 permits the top H to be secured at any desired elevation and this mechanism preferably includes an arcuateshaped clamping plate 66, spot welded or otherwise permanently secured, as at 65, to the outer side of the upper end of one of the upper pivot arms 33. The clamping plate 66 is provided with an arcuate shaped slot 6! having as its center the pivot bolt 32. ,A clamping screw 68, having a clamping knob 69 at its outer end, extends through an opening H in the top flange 28, through the arcuate slot 61 in the clamping plate and is engaged at its inner end by the nut 12, which member is secured to and prevented from turning by the nut plate 13. This nut plate is offset, as shown at 14, to permit its being bolted to the inner surface of the upper flange 28.

Tightening the clamping knob 69 will secure the table top at any desired elevation by binding the clamping plate 66 between the nut plate 13 and the top flange 28.

An elevating table such as We have herein described has many novel features and advantages over prior art devices of similar nature. The spring tensioning device I6 depends only partially upon adjustment of the tension of the springs to compensate for or counterbalance loads of various weights which may be placed upon the table top. The mechanism provides for increasing the leverage applied by the lifting springs to the pivot arms to compensate for increased load.

When the spring tensioning device has been properly adjusted to any particular load, the table top, along with its load, may be readily adjusted as to height by loosening the clamping knob 69 and giving the top a slight push either up or down as desired.

A table embodying our inventive idea is dependable, easy and safe to use, relatively inexpensive to manufacture and suited to a wide variety of uses, particularly in 'oiflces, for supporting ledgers, posting trays, and card files at the height most convenient for the user.

Although we have described a specific embodiment of our invention, it is apparent that modifications thereof may be made by those skilled in the art. Such modifications may be made without departing from the spirit and scope of our invention as set forth in the appended claims.

We claim as our invention:

1. In an elevating table, a base member, a top member disposed thereabove and parallel thereto, at least two parallel arms pivotally connected between the said base and top members, a spring anchored at one of its ends, a lever arm comprising an extension of one of said parallel arms, a tension adjusting member pivotally secured at one end thereof to the free end of the lever arm and at the other end thereof to the free end of the spring, and means for adjusting the angular relation of the tension adjusting member to the lever arm.

2. In an elevating table, a base member, a top member disposed thereabove and parallel thereto, pairs of parallel arms pivotally connected to the base member generally adjacent one end thereof and to the top member generally adjacent the opposite end thereof, the lowermost of said parallel arms having portions thereof extendin beyond the points of pivotal connection with the base and forming lever arms, springs enclosed by the base and anchored at one end thereof, a tension adjusting member pivotally secured at one end thereof to the free ends of the lever arms and at the otherend thereof to the free ends of the springs, and means for adjusting the angular relation of the tension adjusting member to the lever arms.

3. In an elevating table, a base, a table top member disposed in spaced, parallel relation to the base, parallel base flanges mounted in upstanding position adjacent one end of the base, parallel table flanges depending from the opposite end of the table and in generally parallel relation with the base flanges, pairs of parallel arms pivotally connected between the base flanges and the table flanges with the points of pivotal connection to each of said flanges offset vertically whereby the pairs of arms may assume positions parallel to the base when the table top member is in lowered position, lever arms comprising extensions of the lowermost arm of each pair of arms, springs each anchored at one end to the base at positions remote from the lever arms, means securing the springs, at their other ends, to the lever arms, and means for varying the tension on the springs.

4. In an elevating table, a base, a table top member disposed in spaced, parallel relation to the base, parallel base flanges mounted in upstanding position adjacent one end of the base, parallel table flanges depending from the opposite end of the table and in generally parallel relation with the base flanges, pairs of parallel arms pivotally connected between the base flanges and the table flanges with the points of pivotal connection to each of said flanges offset vertically whereby the pairs of arms may assume positions parallel to the base when the table top member is in lowered position, lever arms comprisin extensions of the lowermost arm of each pair of arms, springs each anchored at one end to the base at positions remote from the lever arms, means securing the springs at their other ends to the lever arms, means for varying the tension on the springs, and locking means operatively connected between one of the parallel arms and an adjacent flange and adapted to prevent relative movement therebetween.

5. In an elevating table, a base, a table top member disposed thereabove and generally parallel thereto, parallel base flanges mounted in upstanding position adjacent one end of the base, parallel table flanges depending from the opposite end of the table and in generally parallel relation with the base flanges, pairs of parallel arms pivotally connected between the base flanges and the table flanges with the points of pivotal connection to each of said flanges offset vertically whereby the pairs of arms may assume positions parallel to the base when the table top member is in lowered position, means urging the parallel arms toward a vertical position to thereby elevate the table top member and locking means operatively connected between one of the parallel arms and an adjacent flange for selectively locking said arm and flange members in a plurality of relative positions.

6. In an elevating table, a base, a table top disposed thereabove, pairs of parallel arms pivotally connected therebetween, certain of the arms having extensions beyond the points of pivotal connection with the base, a tension spring anchored at one end thereof to the base at a point remote from the arm extensions, means pivotally connected to the arm extensions at one end thereof and to the free end of the spring at the other end thereof to form a link therebetween, and threaded adjusting means operatively disposed between the said link means and the arm extensions and adapted to vary the angular relation therebetween.

WRIGHT K. GANNETT. GIFFORD M. MAST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 736,886 Smith Aug. 18, 1903 1,074,753 Smouse Oct. 7, 1913 1,714,244 Rowley May 21, 1929 1,824,822 Kradolfer Sept. 29, 1931 1,900,528 Statz Mar. 7, 1933 2,152,946 Barltrop Apr. 4, 1939 2,188,827 Bradfield Jan. 30, 1940 FOREIGN PATENTS Number Country Date 294,303 Italy Mar. 1'7, 1932 

